Engrave Text onto an irregular surface
Your "staff" object has many duplicate vertices and all normals are inside, boolean can't work.


In Edit mode, A to select all, then press W > Remove doubles, 
After fixing duplicates, select all, press Ctrl+N to fix normals
apply boolean modifier to object "staff" with type of Operation set to Difference, with object "Esvele"


In order to see the effect, hide object "Esvele" or set its "maximum draw type" to "bounds".



Adding pictures for the whole process...













I hope it is clearer now... you just have to set boolean for every other text, now, it will work and have the right color......